Technical Field
The present disclosure relates to an agrochemical composition comprising dicamba or its salt, a sulfonamide herbicide free acid and a solid base. The present disclosure also relates to a method of controlling field weeds with the use of the said composition. Furthermore, the present disclosure relates to a method of reducing and/or removing agrochemical composition residues in an application tank, as well as a method of preparing an agrochemical composition, comprising the mixing of a solid base with dicamba or its salt and a sulfonamide herbicide free acid.
Description of Related Art
Sulfonamide herbicides are a class of compounds of high herbicidal activity with sulfonylurea or triazolopyrimidine as core structure. Compared with other conventional herbicides, sulfonamide herbicides show significantly higher herbicidal activity. However, the cost of sulfonamide herbicides is relatively high. In addition, the effect of sulfonamide herbicides on controlling monocotyledonous weeds is better than that on dicotyledonous weeds. Therefore, agrochemical compositions comprising the combined use of a sulfonamide herbicide and other herbicides are known in the art.
The combined use of a sulfonamide herbicide and dicamba or its salt exhibits significant synergism with better controlling effect on monocotyledonous and dicotyledonous weeds. It broadens the herbicidal spectrum, lowers the cost and shortens the farming time. Moreover, application in multiple amount of normal field usage is not only safe to the growing crops, but also safe to the succeeding crops thereafter. CN1169441 discloses an herbicidal formulation for controlling weeds in corn fields, which comprises a mixture of dicamba or its salt and nicosulfuron. The examples disclose a wettable powder of 1% dicamba+6% nicosulfuron; an aqueous suspension of 5% dicamba+1% nicosulfuron; an emulsion concentrate of 9% dicamba+1% nicosulfuron; and an aqueous solution of 39% dicamba+1% nicosulfuron. CN1433688 discloses an herbicidal formulation for controlling weeds, which comprises a mixture of dicamba or its salt and tribenuron-methyl. The examples disclose a wettable powder of 40% dicamba+4% tribenuron-methyl; a dry flowable of 48% dicamba+2% tribenuron-methyl; and a wettable powder of 49% dicamba+1% tribenuron-methyl. CN102365967 discloses an herbicidal composition for wheat fields, which comprises mesosulfuron-methyl and dicamba. The examples disclose a wettable powder of 19.5% dicamba+1% mesosulfuron-methyl; a wettable powder of 29.2% dicamba+1.5% mesosulfuron-methyl; a wettable powder of 39.2% dicamba+1.8% mesosulfuron-methyl; a water-dispersible granule of 34.3% dicamba+1.5% mesosulfuron-methyl; a suspension of 58.3% dicamba+3% mesosulfuron-methyl; and an emulsion concentrate of 50.8% dicamba+1.8% mesosulfuron-methyl. Sulfonamide herbicides are a class of highly active pesticides. Therefore, it is necessary to remove all sulfonamide residues carefully from the spray equipment (spray tank) used for applying pesticides on crops before using it to treat crops sensitive to sulfonamide or that would be damaged by sulfonamide used in the previous application. Adequate cleanout may require a rinsing procedure that is time-consuming and results in wastewater disposal problem. In the examples of CN1169441, the herbicidal mixtures of dicamba and nicosulfuron, formulated as emulsion concentrates, aqueous solutions, aqueous suspensions and wettable powders, have an amount of 1%-6% nicosulfuron. In the examples of CN1433688, the herbicidal mixtures of dicamba and tribenuron-methyl, formulated as wettable powders and dry flowables, have an amount of 1%-4% tribenuron-methyl. In the examples of CN102365967, the herbicidal mixtures of dicamba and mesosulfuron-methyl, formulated as wettable powders, water-dispersible granules, suspensions and emulsion concentrates, have an amount of 1%-3% mesosulfuron-methyl. In the abovementioned herbicidal mixtures of dicamba and sulfonamide, the amount of sulfonamides is relatively low, ranging from 1% to 6%. Since the amount of sulfonamides is low, there may not be any residue remaining in the spray tank or the amount of residue remaining is limited. However, a further increase in the amount of sulfonamides in the mixture of dicamba and sulfonamides inevitably results in sulfonamide residues remaining in the spray tank. Large quantity of water is required to wash the spray tank in order to reduce the amount of insoluble contaminative sulfonamide residues.